1 /* 2 * Copyright (c) 1983, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * $FreeBSD$ 34 */ 35 36 #if defined(LIBC_SCCS) && !defined(lint) 37 static char sccsid[] = "@(#)telldir.c 8.1 (Berkeley) 6/4/93"; 38 #endif /* LIBC_SCCS and not lint */ 39 40 #include <sys/param.h> 41 #include <sys/queue.h> 42 #include <dirent.h> 43 #include <stdlib.h> 44 #include <unistd.h> 45 46 #include "telldir.h" 47 48 /* 49 * The option SINGLEUSE may be defined to say that a telldir 50 * cookie may be used only once before it is freed. This option 51 * is used to avoid having memory usage grow without bound. 52 */ 53 #define SINGLEUSE 54 55 /* 56 * return a pointer into a directory 57 */ 58 long 59 telldir(dirp) 60 DIR *dirp; 61 { 62 struct ddloc *lp; 63 64 if ((lp = (struct ddloc *)malloc(sizeof(struct ddloc))) == NULL) 65 return (-1); 66 lp->loc_index = dirp->dd_td->td_loccnt++; 67 lp->loc_seek = dirp->dd_seek; 68 lp->loc_loc = dirp->dd_loc; 69 LIST_INSERT_HEAD(&dirp->dd_td->td_locq, lp, loc_lqe); 70 return (lp->loc_index); 71 } 72 73 /* 74 * seek to an entry in a directory. 75 * Only values returned by "telldir" should be passed to seekdir. 76 */ 77 void 78 _seekdir(dirp, loc) 79 DIR *dirp; 80 long loc; 81 { 82 struct ddloc *lp; 83 struct dirent *dp; 84 85 LIST_FOREACH(lp, &dirp->dd_td->td_locq, loc_lqe) { 86 if (lp->loc_index == loc) 87 break; 88 } 89 if (lp == NULL) 90 return; 91 if (lp->loc_loc == dirp->dd_loc && lp->loc_seek == dirp->dd_seek) 92 goto found; 93 (void) lseek(dirp->dd_fd, (off_t)lp->loc_seek, SEEK_SET); 94 dirp->dd_seek = lp->loc_seek; 95 dirp->dd_loc = 0; 96 while (dirp->dd_loc < lp->loc_loc) { 97 dp = readdir(dirp); 98 if (dp == NULL) 99 break; 100 } 101 found: 102 #ifdef SINGLEUSE 103 LIST_REMOVE(lp, loc_lqe); 104 free((caddr_t)lp); 105 #endif 106 } 107 108 /* 109 * Reclaim memory for telldir cookies which weren't used. 110 */ 111 void 112 _reclaim_telldir(dirp) 113 DIR *dirp; 114 { 115 struct ddloc *lp; 116 struct ddloc *templp; 117 118 lp = LIST_FIRST(&dirp->dd_td->td_locq); 119 while (lp != NULL) { 120 templp = lp; 121 lp = LIST_NEXT(lp, loc_lqe); 122 free(templp); 123 } 124 LIST_INIT(&dirp->dd_td->td_locq); 125 } 126